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Wilburn C. Russell, 73, pauses in front of the house his son U.S. Army Sgt. John Russell purchased in Sherman, Texas, Tuesday, May 12. Russell's son is accused of killing five fellow troops at their base in Iraq.

BAGHDAD — The U.S. military command launched an investigation Tuesday into whether it offers adequate mental health care to its soldiers, a day after a sergeant finishing up his third tour of Iraq allegedly shot and killed five comrades at a clinic on a U.S. base.

Sgt. John M. Russell, 44, of Sherman, Texas, was taken into custody outside a mental health clinic at Camp Liberty following Monday’s shooting and charged with five counts of murder and one of aggravated assault, Maj. Gen. David Perkins said.

The case, the deadliest of the war involving soldier-on-soldier violence, has cast a spotlight on combat stress and emotional problems resulting from frequent deployments to battle zones in Iraq and Afghanistan.

Up to one-fifth of the more than 1.7 million who have served in the two conflicts are believed to have symptoms of anxiety, depression and other emotional problems. Some studies show that about half of those who need help do not seek it.

Russell’s father said his son, who joined the Army in 1994 after a divorce and minor scrapes with the law, felt poorly treated at the stress center. He said he hopes “we find he snapped because of the pressure. He wasn’t a mean person.”

In Baghdad, Perkins told reporters that Russell, a communications specialist assigned to the 54th Engineer Battalion from Bamberg, Germany, was sent to the mental health clinic by his superiors, presumably because of concern over his emotional state.

A Pentagon official said that Russell was escorted to the clinic, but was asked to leave after he argued with the staff. The soldier then reportedly left, seized his escort’s weapon, returned to the clinic and opened fire.

In addition to the ongoing criminal investigation, Perkins said the U.S. command had opened a formal inquiry into the “general availability” of health care for American service personnel in Iraq, “specifically the policies and procedures surrounding behavioral health services.”

He gave no further details and did not say how the investigation was being conducted.

The U.S. military has become increasingly concerned about mental health in the ranks following a steady rise in suicides — which the Army says have increased worldwide from at least 102 in 2006 to 140 last year. As of April, the Army had reported at least 48 suicides.

Thousands of other veterans are believed to suffer flashbacks, nightmares or fits of anger as they attempt to readjust to civilian life.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Post-traumatic stress disorder“One thing if we’ve learned from this war, we learned from World War II, Korea, Vietnam, the previous wars, is not all injuries are physical,” said Maj. Gen. Daniel P. Bolger, commander of Multi-National Division-Baghdad.

To cope with the stress, the Army has set up clinics on most major bases in Iraq, staffing them with psychologists, psychiatrists, social workers and other specialists.

Commanders, chaplains and others in leadership positions are also trained to watch for signs of stress and refer soldiers to mental health professionals if needed.

However, some officials believe soldiers are reluctant to take advantage of the facilities because of the stigma attached to counseling in a military culture that promotes mental and physical toughness.

Last November, Army Secretary Pete Geren said combating the stigma “is a challenge” throughout American society, especially in the Army “where we have a premium on strength, physically, mentally, emotionally.”

However, Bolger said the command was encouraging soldiers to take advantage of clinics if they feel under stress.

“We’ve encouraged people to do self-referral,” Bolger said. “We’ve actually encouraged them to say, ‘Hey, we’re not going to hold this against you, we’d rather have you self-refer’ ... than have an incident that would be tragic.”